e engraving is strongest,[D] then
cut off the upper part or sky, and fix that on another frame.

[Illustration: Fig. 14.]

[Illustration: Fig. 15.]

The prints being thus prepared, place them in a box, A B C D, Figs. 14
and 15, the opening to which, E F G H, should be a little less than
the print. Cover this opening with a glass, and paint all the space
between that and the prints, which should be about two or three
inches, black. The frame that contains the sky should be about an inch
behind the other. In the back part of this box, which is behind the
prints, and which may be about four inches deep, place four or five
small candlesticks to hold wax lights, and cover that part entirely
with tin, that it may be the more luminous.

When the print is placed between the wax lights and the opening in the
front of the box, and there is no other light in the room, the effect
will be highly pleasing; especially if the lights are at a sufficient
distance from each other, and not too strong, that they may not
occasion any blots in the print. Those prints that represent the
rising or setting of the sun will have a very picturesque appearance.
Such as represent conflagrations have also a striking effect.

There should be two grooves for the print next the glass, that you may
insert a second subject before you draw away the first; and that the
lights in the back of the box may not be discovered.

You must not, thinking to make the print more transparent, cover it
with varnish; for that will prevent the gradation of the colours from
being visible. The frame should enter the side of the box by a groove,
that a variety of subjects may be introduced.

[D] When you colour a print, place it before you, against a
piece of glass, in a position nearly erect, that it may be
enlightened by the sun. You may also colour both sides of the
print.

EXPERIMENTS IN MAGNETISM.

_The Magnetic Wand._

Bore a hole three-tenths of an inch in diameter, through a round stick
of wood; or get a hollow cane about eight inches long, and half an
inch thick. Provide a small steel rod, and let it be very strongly
impregnated with a good magnet: this rod is to be put in the hole you
have bored through the wand, and closed at each end by two small ends
of ivory that screw on, different in their shapes, that you may better
distinguish the poles of the magnetic bar.

When you present the north pole of this wand to the south[E] pol